Partial cellulose ethers with strong anion exchange properties



R- J- BERNI ETAL Sept. 2, 1969 PARTIAL CELLULOSE ETHERS WITH STR ONG ANION EXCHANGE PROPERTIES Filed May 2, 1967..

503% uz 82 ho 0 0 INVENTORS RALPH J. BERN! RUTH R. BENERITO BY JOHN B. McKELVEY ATTORNEYS United States Patent 3,464,781 PARTIAL CELLULOSE ETHERS WITH STRONG ANION EXCHANGE PROPERTIES Ralph J. Berni, Ruth R. Benerito, and John B. McKelvey, New Orleans, La., assignors to the United States of America as represented by the Secretary of Agriculture Filed May 2, 1967, Ser. No. 635,986 Int. Cl. D06m 13/34; C081) 11/20 US. Cl. 8-1161 3 Claims ABSTRACT OF THE DISCLOSURE A non-exclusive, irrevocable, royalty free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

A primary object of the present invention is to provide a method for preparing at will some cellulose ethers with strong anion exchange properties and improved wet and dry crease recovery.

Prior art processes are known for the preparation of strong base anion exchanges to partially convert diethylaminoethylated cotton to the quaternary form by refluxing in 10% CH I in absolute alcohol. Benerito (Benerito, R. R., Woodward, B. B., and Guthrie, J. D., Anal. Chem, 37, 1693 (1965) found that a large number of tertiary amines could be converted to quaternary groups by using the same method of Hofipauir and Guthrie (Hoffpauir, C. L, and Guthrie, J. D., Text. Res. J. 20, 617 (1950)). However, it was necessary to treat the fibers under completely anhydrous conditions.

In contrast to prior art processes for the formation of quaternary amino groups on cellulose, this invention produces such a product without the need for maintaining anhydrous conditions which often prove unworkable in normal commercial processes. Also no CH I reflux period is necessary since the quaternary groups formed in situ through direct interaction between epichlorohydrin and triethyl or thiethanol amine as shown below:

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In addition some reaction between the NaOH treated cellulose and epichlorohydrin takes place to improve the wet resiliency of the fabric. The product formed also has increased dry crease recovery and is titrated as a strong base exchanger.

The present invention includes pretreatment of cotton fabric with solutions of NaOH ranging from 828% by weight before immersing the rolled fabric into a 3 :1 mole ratio solution of epichlorohydrin and triethyl or triethanol amine. The fabric is allowed to react in the epichlorohydrin and triethyl or triethanol amine solution for 1.5 to 24 hours. The fabric is then removed from the reaction vessel and washed with tap Water, neutralized in acetic acid and then washed in methanol and again with water. The reacted fabric is then dried and equilibrated.

To determine the ion exchange, an accurately-weighed sample of sutficient weight to give approximately 0.8 meq. of replaceable anion was placed in a titration flask containing exactly 50.00 ml. of a salt solution prepared with conductivity water and kept in a nitrogen atmosphere. The sample was allowed to equilibrate overnight in the titration flask while being stirred with nitrogen gas bubbled first into a bubbler containing the given solution before being bubbled into the titration flask to minimize concentration changes in the flask. All potentiometric titrations were carried out in specially designed cells of approximately 250 ml. capacity having four ground glass outlets to accommadate the microburet in the center, and inlet-outlet tube for nitrogen, the glass electrode, and the saturated calomel electrode. All pH measurements were made with a Beckman Model GS pH meter to- $0.05 pH unit. Each titration required from 8-12. hours because the time required in some instances for establishment of equilibrium. FIGURE I illustrates the curves of strong (A) and weak (B) ion exchange cotton.

Example 1 Approximately 10.0 of 48" x 72 cotton fabric (desized, scoured, and bleached) was twice padded to pickup with 28% NaOH and then immersed in a graduate cylinder containing 60 m1. of epichlorohydrin (0.75 mole) and 35 ml. of triethanolamine (0.25 mole). After 19 hours reaction time, the fabric was removed from the recation medium and neutralized with acetic acid and tap Water. The fabric was then rinsed three times in methanol, quenched in tap water and finally with distilled Water. The fabric was then ironed dry and allowed to equilibrate for 16 hours before weighing. The treated fiber had a weight add-on of 12.6%, a nitrogen content of 0.52%, a dry or conditioned crease recovery value of 236 and 285 (W+F) respectively. The treated fabric was then ground in a Wiley Mill and titrated as a strong base anion exchange resin.

Example 2 A 68" x 72" fabric was treated as in Example 1 with two exceptions. Triethylamine was used instead of triethanol amine in the reaction with epichlorohydrin and secondly, the reaction time was decreased from 19 hours to 4 hours. The treated fabric had a weight add-on of 9.5%, a nitrogen content of 0.20%, a dry or conditioned crease recovery value of 238 (W+F) and a Wet crease recovery value of 242 (W+F). The fabric was then titrated as a strong base anion exchange resin.

3 4 Example 3 2. The process of claim 1 wherein the member is triethyl amine. The following properties were obtained using a proce- 3. The process of claim 1 wherein the member is tridure as in Example 2. ethanol amine.

Percent Sample NaOH Reaction Percent N o. pretreatment time (hrs) add-on Percent N Dry (W-i-F) Wet (W+F) 8 7. 5 15. 0. 51 246 252 s 16. 2 20. 0 0. 59 257 226 23 o. 2. 9 Trace 206 237 23 1. 9 6. 0 0. 14 182 257 23 4. 5 16. s 0. 34 154 308 All but sample three showed strong anion exchange References Cited g f UNITED STATES PATENTS e a1 1. A process for producing a partial cellulose ether in 3135 1,420 11/1967 McKelvey et 8 116-2 fabric form, comprising 3,243,426 3/ 1966 Caesar 260--233.3 (a) padding a cotton fabric to a 100% pickup With an 3,102,112 8/1963 Carter at 260-212 aqueous solution of sodium hydroxide having a con- 2,876,217 3/1959 Paschan 260233-3 centration of at least by i 2,710,861 6/1955 Charles 61: al. 260212 (b) reacting the thus-padded cotton fabric with a 3:1 2,664,360 12/1953 Charles et 106123 mole ratio solution of epichlorohydrin and a member selected from the group consisting of triethyl DONALD CZAJA Pnmary Examiner amine and triethanol amine for at least .5 hour at R. W. GRIFFIN, Assistant Examiner room temperature;

(0) washing the reacted fabric free of reagents, ironing US. Cl. X.R.

it dry, and allowing it to equilibrate for 16 hours. 260231 

